Vaporization of organic materials from open tanks caused by exposure to normal indoor or medium to high outdoor temperatures provides danger to humans from the toxic effect on their bodies, as well as destruction of the earth's atmosphere, explosion hazards and fire dangers. Chlorinated organic materials provide a special danger due to toxic effect on humans and the effect on all components of the earth's atmosphere, including water vapor, oxygen, ozine, carbon dioxide and sunlight.
Attempts have been made to control the problem of vaporization from the standpoint of explosion and fire hazards by the use of an inert gas blanket such as nitrogen. This method did nothing to prevent vaporization of the organic material, but did provide an environment that prevents the combination of the organic material with oxygen, thus preventing fire and explosions.
Control of vaporization of organic materials has been limited to open ventilation systems, that in all cases result in discharge into the atmosphere of large amounts of organic material with the accompanying slow destruction of the air quality.
The present invention provides cooling of a recirculated gas stream, as well as a condenser for the recycle of the organic material in an enclosed chill gas blanket over the top surface of the liquid.
Collection and return of the condensed vapors provide a special problem due to the gas flow across the liquid surface of the tank and in the condenser section of the system. To avoid entrainment of the condensed vapor, a liquid collection ring is used in the top of the chilled water collector header of the condenser heat transfer unit. After collection, the liquid is returned by a drain pipe to the tank at a point below the surface of the liquid. This is an important factor in allowing the flow of gas across the surface of the liquid which is an opposite design approach to the past vaporization control systems which limited the amount of gas flow in order to limit vaporization.